Random Thought on the Variation in Animal Behavior

I love nature shows, but I'm always alarmed at the confidence with which folks like Steve Irwin and Jeff Corwin approach dangerous animals. They consistently refer to the exhaustive body of research on these animals as evidence of what these critters will do from moment to moment. This seems odd to me, even though the fact Corwin and Irwin are still alive reasonably substantiates their credibility. What gets me is this: how is that human tendencies have so much variation but animals are fairly well predictable?

I mean, there are good people who adhere to social norms, but there are also bad people, even evil people, who have no regard for others. The behavior of these kinds of people cannot be even remotely predicted. Are there not equivalents in the animal kingdom? Are there not "bad seeds" who, far from doing what researchers expect, will jump at the opportunity to maul a supremely arrogant human? This thought grips me most when I see marine biologists swim with sharks. Wasn't the shark in Jaws one of these bad seeds? I know, it's just Hollywood, but still. I saw a show a couple of nights ago where a guy was swimming with no weapons and in no cage with a slew of bull sharks. He was obviously very comfortable - the crazy bastard. Why is it that the behavior of such dangerous animals can be predicted so consistently, yet humans are all over the map?

Maybe it's human culture that builds in so much variation in behavior. I don't know, but you can count on one thing - if I ever encounter a bunch of bull sharks, I'm exiting the water immediately.